New British Freshwater Algse. By W. and G. S. West. 159 
St. punctulatum Breb. The two species are however quite distinct. 
Moreover, St. Kjelmanni occurs only in subalpine and alpine localities 
in the British Isles ; we have met with it in mountain tarns and 
springs in many places, but never in lowland districts. (Of. Boy et 
Biss., Scottish Lesm., p. 3). 
31. S. brachiatum Balfs (Brit. Pesm., p. 131, t. xxiii. fig. 9). 
PI. IV. figs. 53-6. 
An adult zygospore of this (from Thursley Common, Surrey) was 
observed (long. 42 /x, lat. 31 /x) which differed from all those we have 
previously noticed in having the angles rounded and scarcely pro- 
duced. 
A large number of examples in various stages of division were 
observed from Slieve Donard, Co. Down, Ireland, which were dividing 
in an abnormal manner. After the division of one plant, but before 
the separation of the two individuals, and while the new semicells are 
as yet young and without any trace of processes, either one or both 
of the plants divide, the result being, that there are but two adult 
semicells, and between them (still in connection) either four (fig. 55) 
or six (fig. 56) young semicells without processes. 
32. S. micron sp. n. PI. IY. figs. 50-51. 
S. minutum, circiter tarn latum quam longum (cum pro- 
cessibus), profunde constrictum ; semicellulse obverse semi- 
circulares, apicibus leviter convexis, angulis superioribus in 
processus breves validos divergentes productis, processus cum 
annulis duobus spinarum brevium (4 annulo unoquoque) 
prope basem vestiti, apicibus processuum dilatatis truncatisque, 
et cum spinis tribus brevibus; a vertice visae triangulares, 
lateribus concavis, angulis in processus breves dilatatos et 
trispinosos productis. 
Long. s. proc. 8*5-11*5 /x, c. proc. 12-17’ 5 ycx; lat. s. 
proc. 7-9*5, c. proc. 12*5-19 /x; lat. isthm. 3-3*5 /x. 
Hah. Puttenham. Common, Surrey. In great profusion 
with other desmids amongst Utricularia minor. 
This minute species has very constant characters which render it 
easy of distinction. It is nearest to St. pseudotetracerum (Nordst.) 
W. and G. S. West (Fresh w. Alg. of Madagascar, Trans. Linn. Soc. 
Oct. 1895, p. 79, pi. viii. fig. 39 ; St. contortum Delp. var. pseudo- 
tetracerum (Nordst.) Freshw. Alg. of New Zeal, and Austr., p. 37, 
t. iv. f. 9), but it is much smaller, the arms are more robust and 
shorter, and the spines at the dilated apices of the processes and the 
two rings of short spines at their base distinguish it. Compare with 
St. sp. Turn. (Freshw. Alg. of E. India, p. 126, t. xv. f. 22). 
33. S. Picum sp. n. PI. IY. fig. 49. 
S. parvum, paullo latius quam longius, profunde constric- 
tum, sinu aperto et subacuminato ; semicellulae elliptico- 
